Air heater with internal combustion chamber

ABSTRACT

An air heater with an internal combustion chamber is supplied with gas from an externally provided burner which can be shut off from the combustion chamber by means of a hot gas slide valve. This valve lies between the burner and an elbow, with a refractory lining. A water-cooled support ring provides a thermal barrier between the elbow and a transition pipe to couple the burner output to the combustion chamber. A hot air exhaust opening controlled by a slide valve is arranged in the combustion chamber to overlie the point of entry of hot gases from the burner.

[111 3,824,070 1451 July 16,1974

1 1 AIR HEATER WITH INTERNAL COMBUSTION CHAMBER [75] Inventor: Friedrich-Wilhelm Drebes, Bochum,

Germany [73] Assignee: Dr. C. Otto & Comp. G.m.b.H.,

Bochum, Germany [22] Filed: Mar. 26, 1973 [21] Appl No.: 345,211

[30] Foreign Application Priority Data May 13, 1972 Germany 2223442 [52] US. Cl. 432/214, 432/217 [51] Int. Cl F23I 9/04 [58] Field of Search 432/214, 217, 218, 222

[56] References Cited UNITED STATES PATENTS 1,656,542 1/1928 Stoecker et a1 432/214 1,689,042 10/1928 McGee 1,825,259 9/1931 Brassert... 432/217 3,642,262 2/1972 Vroege 432/217 Primary Examiner'.l0hn J. Camby Attorney, Agent, or FirmBrown, Murray, Flick & Peckham 1571 ABSTRACT An air heater with an internal combustion chamber is supplied with gas from an externally provided burner which can be shut off from the combustion chamber by means of a hot gas slidevalve. This valve lies between the burner and an elbow, with a refractory lining. A water-cooled support ring provides a thermal barrier between the elbow and a transition pipe to couple the burner output to the combustion chamber. A hot air exhaust opening controlled by a slide valve is arranged in the combustion chamber to overlie the point of entry of hot gases from the burner.

7 Claims, 6 Drawing Figures PATENIED JUL 1 51974 $HEET 10F g- ////////l I I I I II mv T,

AIR HEATER WITH INTERNAL COMBUSTION CHAMBER BACKGROUND OF THE INVENTION This invention relates to an air heater incorporating an internal combustion chamber which is supplied with gas by a burner arranged ahead of the combustion chamber in the manner such that slide valves are used to terminate the flow of hot gas to the combustion chamber. Air heaters with an internal combustion chamber have, operationally, been proven superior to air heaters with an externally arranged combustion chamber. With respect to an external combustion chamber, high stresses occur in the elongated cupola when cold air is injected into the chamber. Moreover, the brick lining of the cupola and the tight connection between the combustion chamber and the cupola present considerable technical problems. With respect to an air heating arrangement with an internal combustion chamber, the accessibility to the combustion chamber is limited and thereby rendering it difficult to perform the unavoidable repairs needed from time to time. Long interruptions to the operation occur because the air heater must be cooled, thus seriously affecting economical operation of the heater.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved construction for air heaters wherein the advantages of an internal combustion chamber are realized while providing an external burner arranged ahead of the chamber so that accessibility to the combustion chamber is provided and different kinds of burners may be employed.

It is a further object of the present invention to provide an air heater with an internal combustion chamber supplied with gas from an externally located burner whereby the burners may be serviced, maintained and, if desired, replaced without undue delays causing long interruptions to the operation of the air heater.

According to the present invention, there is provided an air heater comprising the combination including a burner for supplying combustion gases for the air heater, valve means for controlling the delivery of hot gas from the burner, an elbow having a refractory lining receiving gas from the burner, a combustion chamber for receiving gas discharged from the .elbow. the combustion chamber including a hot air discharge opening, and valve means for controlling the passage of air through said discharge opening. The preferred embodiment of the present invention further includes a transition conduit member for conducting gas into the combustion chamber from the aforementioned elbow, and a water-cooled support ring at the interconnection between the elbow and the transition conduit member. The invention further provides that the opening of the transition pipe at its upper end is matched to the crosssectional opening of the combustion chamber. The

FIG. 1 is a sectional view taken vertically through a hot air heater arrangement according to the present invention;

FIG. 2 is a sectional view taken FIG. 1;

FIG. 3 is a sectional view takenalong line III- -III of FIG. 1;

FIG. 4 is a sectional view taken along line IVIV of FIG. 1;

FIG. 5 is an enlarged sectional view taken along line V--V of FIG. 1; and

FIG. 6 is an enlarged sectional view taken along lin VI-VI of FIG. 4. I

With reference now to FIG. 1 of the drawings, there isillustrated an air heater provided with checkerwork 10 forming a refractory lining for the storage of heat within the walls 11 of the air heater. The walls 11 are further defined by an outer metallic wall casing 12. FIGS. 1 and 3 illustrate a collecting distributing chamber 13 located at the bottom of the heater. This chamber is provided with connection pipes 14 for the exhaust of combustion gases into a conventional stack, not shown, and the provision of a connecting pipe 15 for the entry of air to be heated by the heater and then drawn off through a combustion chamber 16 by way of pipe 15A. The hot air leaves the combustion chamber 16 by passing through an opening 17 forming a stream or blast of hot air. A water-cooled slide valve 18 may be controlled to block the flow of hot air through the pipe 15A.

The floor of the combustion chamber has a hot gas discharge opening 19 underlying the hot air exhaust opening 17 whereby hot gases entering the combustion along line II-II (3f chamber through the opening 19 are thoroughly mixed with the hot air for enhancing combustion within the chamber. A transition piece in the form of a coupling member 20 is lined with refractory material for the discharge of hot gases into the opening 17. The coupling member is attached at one end to the combustion chamber and has at the other end a thermal barrier provided by a water-cooled support ring 21 which is illustrated in greater detail in FIGS. 5 and 6. As can be readily seen, the water-cooled support ring has an internal chamber supplied with water by pipes 21A spaced about the periphery of the ring where there is also provided drain lines 21B for the circulation of water through the chamber and the ring. Arranged below the coupling member for engagement with the lower surface of the coolant ring 21 there is an elbow 22 which is also lined with refractory material. The elbow has a horizontal leg 22a extending toward a burner 24 which engages a support 25. A water-cooled, hot gas slide valve 23 forms the interconnection between the burner 24 and the elbow 22. An inlet pipe 26 supplies hot gas to the burner 24 and a pipe 27 supplies air to the burner.

As shown in FIGS. 2 and 3, when viewed vertically, the horizontal axis of the burner extends in a direction such that it forms an acute angle with the overlying horizontal axis of the pipe 15A. By providing this arrangement of parts, access can be readily gained to the slide valves 18 and 23 wherebythey can be operated independently of each other. It will also be observed that by this construction, the burner is independent of the construction of the air heater. It will further be observed that the coupling member 20 and the elbow 22 can be readily disconnected from each other so that the combustion chamber 16 can be made readily accessible when desired.

This air heater arrangement brings about many useful advantages which include preventing excess thermal stressing of the various parts in the combustion chamber. The length of the combustion chamber in a series arrangement of the burner is sufficient for complete combustion of the gases used for heating. A more uniform burning of the gaseous mixture is accomplished for the air heaters in the case of a cupola. As can be readily seen from FIG. 1, the burner is made readily accessible from the outside whereby it can be easily exchanged and replaced without undue delays. The burners may be built from metal parts even when very high combustion temperatures inside the combustion chamber are to be obtained.

Although the invention has been shown in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

I claim as my invention:

1. An air heater apparatus comprising, a combustion chamber having an exhaust opening for discharging heated air from said chamber, first valve means for blocking the flow of hot air exhausted through said opening from said combustion chamber, a burner disposed remote to said combustion chamber for discharging hot gases through an opening in said combustion chamber located below said exhaust opening, second valve means for blocking the flow of hot gas between said burner to said combustion chamber, and

elbow means having a refractory lining for the delivery 2. The air heater apparatus according to claim 1 wherein said first and second valve means are each further defined to include a hot air slide valve and a hot gas slide valve, respectively.

3. The air heater apparatus according .to claim 2 wherein said first and second valve means are each further defined as water-cooled slide valves.

4. The air heater apparatus according to claim 1 wherein said combustion chamber includes a hot gas discharge opening in a wall defining said combustion chamber at a point located above said inlet opening, said apparatus further comprising a coupling member for conducting hot gas to said opening in the combustion chamber located below said exhaust opening, and a fluid-cooled support ring for providing a thermal barrier at the interconnection between said coupling member and said elbow means.

5. The air heater apparatus according to claim 1 wherein said combustion chamber includes a refractory lining through which there is formed a hot gas discharge opening underlying said exhaust opening, said apparatus further comprising support means for said elbow means, and thermal insulation forming supporting connection of said elbow means to the refractory lining of said combustion chamber.

6. The air heater apparatus according to claim 5 further comprising a coupling member having an internal opening for conducting hot gas to said combustion chamber, said thermal insulation extending between said elbow and said coupling member.

7. The air heater apparatus according to claim 1 wherein said hot gas discharge opening extends from below said combustion chamber and through the floor thereof. 

1. An air heater apparatus comprising, a combustion chamber having an exhaust opening for discharging heated air from said chamber, first valve means for blocking the flow of hot air exhausted through said opening from said combustion chamber, a burner disposed remote to said combustion chamber for discharging hot gases through an opening in said combustion chamber located below said exhaust opening, second valve means for blocking the flow of hot gas between said burner to said combustion chamber, and elbow means having a refractory lining for the delivery of hot gas from said burner to said combustion chamber at a point underlying said exhaust opening.
 2. The air heater apparatus according to claim 1 wherein said first and second valve means are each further defined to include a hot air slide valve and a hot gas slide valve, respectively.
 3. The air heater apparatus according to claim 2 wherein said first and second valve means are each further defined as water-cooled slide valves.
 4. The air heater apparatus according to claim 1 wherein said combustion chamber includes a hot gas discharge opening in a wall defining said combustion chamber at a point located above said inlet opening, said apparatus further comprising a coupling member for conducting hot gas to said opening in the combustion chamber located below said exhaust opening, and a fluid-cooled support ring for providing a thermal barrier at the interconnection between said coupling member and said elbow means.
 5. The air heater apparatus according to claim 1 wherein said combustion chamber includes a refractory lining through which there is formed a hot gas discharge opening underlying said exhaust opening, said apparatus further comprising support means for said elbow means, and thermal insulation forming supporting connection of said elbow means to the refractory lining of said combustion chamber.
 6. The air heater apparatus according to claim 5 further comprising a coupling member having an internal opening for conducting hot gas to said combustion chamber, said thermal insulation extending between said elbow and said coupling member.
 7. The air heater apparatus according to claim 1 wherein said hot gas discharge opening extends from below said combustion chamber and through the floor thereof. 